Refrigerant cycle system

ABSTRACT

A refrigerant cycle system includes a primary-side cycle that circulates a first refrigerant, a secondary-side cycle that circulates a second refrigerant, and a cascade heat exchanger that exchanges heat between the first refrigerant and the second refrigerant. The primary-side cycle includes a primary-side connection pipe. The secondary-side cycle includes a secondary-side connection pipe. The primary-side connection pipe includes a primary-side gas connection pipe and a primary-side liquid connection pipe. The secondary-side connection pipe includes a secondary-side gas connection pipe and a secondary-side liquid connection pipe. The pipe diameter of the secondary-side gas connection pipe is smaller than the pipe diameter of the primary-side gas connection pipe, or the pipe diameter of the secondary-side liquid connection pipe is smaller than the pipe diameter of the primary-side liquid connection pipe.

TECHNICAL FIELD

The present disclosure relates to a refrigerant cycle system including acascade heat exchanger.

BACKGROUND

PTL 1 (Japanese Patent Application Laid-Open Publication No. 2014-74508)discloses a refrigerant cycle system including a cascade heat exchanger.By introducing a cascade heat exchanger, a refrigerant cycle systemconstitutes a dual refrigerant cycle that includes a primary-side cycleincluding a heat-source heat exchanger and a secondary-side cycleincluding a usage heat exchanger.

Compared with a single refrigerant cycle that includes no cascade heatexchanger, the flow speed of refrigerant tends to be slow in asecondary-side cycle of a dual refrigerant cycle. In this case, arefrigerating-machine oil that has flowed out from a compressor does noteasily return again to the compressor.

SUMMARY

A refrigerant cycle system according to one or more embodiments includesa vapor compression primary-side cycle that circulates a firstrefrigerant, a vapor compression secondary-side cycle that circulates asecond refrigerant, and a cascade heat exchanger that exchanges heatbetween the first refrigerant and the second refrigerant. Theprimary-side cycle includes a heat-source heat exchanger for giving coldor heat to the first refrigerant, and a primary-side connection pipethat connects the cascade heat exchanger and the heat-source heatexchanger. The secondary-side cycle includes a usage heat exchanger forusing the cold or the heat obtained by the second refrigerant from thecascade heat exchanger, and a secondary-side connection pipe thatconnects the cascade heat exchanger and the usage heat exchanger. Theprimary-side connection pipe includes a primary-side gas connection pipeand a primary-side liquid connection pipe. The secondary-side connectionpipe includes a secondary-side gas connection pipe and a secondary-sideliquid connection pipe. The pipe diameter of the secondary-side gasconnection pipe is smaller than the pipe diameter of the primary-sidegas connection pipe, or the pipe diameter of the secondary-side liquidconnection pipe is smaller than the pipe diameter of the primary-sideliquid connection pipe.

According to this configuration, the pipe diameter of the connectionpipe in the secondary-side cycle is smaller than the pipe diameter ofthe connection pipe in the primary-side cycle. Consequently, it ispossible to increase the flow speed of refrigerant in the secondary-sidecycle. Therefore, a refrigerating-machine oil that has flowed out fromthe compressor easily returns to the compressor.

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 4.5 kW or more and 5.6 kW or less. The pipediameter of the secondary-side gas connection pipe is 7.9 mm ( 5/16inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 7.1 kW or more and 9.0 kW or less. The pipediameter of the secondary-side gas connection pipe is 9.5 mm (⅜ inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 16 kW or more and 22.4 kW or less. The pipediameter of the secondary-side gas connection pipe is 12.7 mm (½inches). In a refrigerant cycle system according to one or moreembodiments, the second refrigerant is carbon dioxide. The refrigeratingcapacity of the secondary-side cycle is 5.6 kW or more and 8.0 kW orless. The pipe diameter of the secondary-side liquid connection pipe is4.8 mm ( 3/16 inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 11.2 kW or more and 16 kW or less. The pipediameter of the secondary-side liquid connection pipe is 6.4 mm (¼inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 16 kW or more and 28 kW or less. The pipediameter of the secondary-side liquid connection pipe is 7.9 mm ( 5/16inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is carbon dioxide. The refrigerating capacity of thesecondary-side cycle is 33.5 kW or more and 45 kW or less. The pipediameter of the secondary-side liquid connection pipe is 9.5 mm (⅜inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R32. The refrigerating capacity of thesecondary-side cycle is 16 kW or more and 22.4 kW or less. The pipediameter of the secondary-side gas connection pipe is 15.9 mm (⅝inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R32. The refrigerating capacity of thesecondary-side cycle is 2.8 kW or more and 3.6 kW or less. The pipediameter of the secondary-side liquid connection pipe is 4.8 mm ( 3/16inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R32. The refrigerating capacity of thesecondary-side cycle is 14 kW or more and 16 kW or less. The pipediameter of the secondary-side liquid connection pipe is 7.9 mm ( 5/16inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R32. The refrigerating capacity of thesecondary-side cycle is 28 kW or more and 33.5 kW or less. The pipediameter of the secondary-side liquid connection pipe is 9.5 mm (⅜inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R454B. The refrigerating capacity of thesecondary-side cycle is 9.0 kW or more and 11.2 kW or less. The pipediameter of the secondary-side gas connection pipe is 15.9 mm (⅝inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R454B. The refrigerating capacity of thesecondary-side cycle is 16.0 kW or more and 22.4 kW or less. The pipediameter of the secondary-side gas connection pipe is 19.1 mm (¾inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R454B. The refrigerating capacity of thesecondary-side cycle is 16 kW or more and 22.4 kW or less. The pipediameter of the secondary-side liquid connection pipe is 9.5 mm (⅜inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R454B. The refrigerating capacity of thesecondary-side cycle is 45 kW or more and 56 kW or less. The pipediameter of the secondary-side liquid connection pipe is 12.7 mm (½inches).

In a refrigerant cycle system according to one or more embodiments, thesecond refrigerant is R454B. The refrigerating capacity of thesecondary-side cycle is 85 kW or more and 109 kW or less. The pipediameter of the secondary-side liquid connection pipe is 15.9 mm (⅝inches).

In a refrigerant cycle system according to one or more embodiments, thepipe diameter of the secondary-side gas connection pipe is less than orequal to 90% of the pipe diameter of the primary-side gas connectionpipe, or the pipe diameter of the secondary-side liquid connection pipeis less than or equal to 90% of the pipe diameter of the primary-sideliquid connection pipe.

In a refrigerant cycle system according to one or more embodiments, acompression ratio of the secondary-side cycle is smaller than acompression ratio of the primary-side cycle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a refrigerant cycle system 100 accordingto a first embodiment.

DETAILED DESCRIPTION

(1) Overall Configuration

FIG. 1 illustrates a refrigerant cycle system 100. The refrigerant cyclesystem 100 is configured to acquire cold or heat from a heat source andsupply the cold or the heat to a user. Here, the “acquire cold from aheat source” means releasing heat to the heat source. The “acquire heatfrom a heat source” means absorbing heat from the heat source. The“supply the cold to a user” means absorbing heat from an environment inwhich the user is present. The “supply heat to a user” means releasingheat into an environment in which the user is present.

The refrigerant cycle system 100 includes one heat source unit 10, onecascade unit 30, and one usage unit 50.

The heat source unit 10 and the cascade unit 30 are connected to eachother to configure a primary-side cycle 20. The primary-side cycle 20 isa vapor compression circuit that circulates a first refrigerant.

The cascade unit 30 and the usage unit 50 are connected to each other toconfigure a secondary-side cycle 40. The secondary-side cycle 40 is avapor compression circuit that circulates a second refrigerant. Thefirst refrigerant and the second refrigerant may be the same refrigerantand may be different refrigerants.

(2) Detailed Configuration

(2-1) Heat Source Unit 10

The heat source unit 10 acquires cold or heat from outside air that is aheat source. The heat source unit 10 includes a compressor 11, afour-way switching valve 12, a heat-source heat exchanger 13, aheat-source expansion valve 14, a subcooling expansion valve 15, asubcooling heat exchanger 16, a liquid shutoff valve 18, and a gasshutoff valve 19.

The compressor 11 sucks and compresses low-pressure gas refrigerant thatis the first refrigerant and discharges high-pressure gas refrigerant.The four-way switching valve 12 makes connection indicated by the solidlines in FIG. 1 during cooling operation and makes connection indicatedby the broken lines in FIG. 1 during heating operation. The heat-sourceheat exchanger 13 exchanges heat between the first refrigerant andoutside air. The heat-source heat exchanger 13 functions as a condenserduring cooling operation and functions as an evaporator during heatingoperation. The heat-source expansion valve 14 adjusts the flow rate ofthe first refrigerant. The heat-source expansion valve 14 also functionsas a decompression device that decompresses the first refrigerant.

The subcooling expansion valve 15 produces cooling gas by decompressingthe first refrigerant that circulates. The subcooling heat exchanger 16exchanges heat between the first refrigerant that circulates and thecooling gas, thereby giving a degree of subcooling to the firstrefrigerant.

The liquid shutoff valve 18 and the gas shutoff valve 19 shut off a flowpath in which the first refrigerant circulates, for example, during workof installation of the heat source unit 10.

(2-2) Cascade Unit 30

The cascade unit 30 is configured to exchange heat between the firstrefrigerant and the second refrigerant.

The cascade unit 30 includes a primary-side expansion valve 31, asecondary-side expansion valve 32, a compressor 33, a four-way switchingvalve 34, a cascade heat exchanger 35, a liquid shutoff valve 38, and agas shutoff valve 39.

The primary-side expansion valve 31 adjusts the amount of the firstrefrigerant that circulates in the primary-side cycle 20. Theprimary-side expansion valve 31 also decompresses the first refrigerant.

The secondary-side expansion valve 32 adjusts the amount of the secondrefrigerant that circulates in the secondary-side cycle 40. Thesecondary-side expansion valve 32 also decompresses the secondrefrigerant.

The compressor 33 sucks and compresses low-pressure gas refrigerant thatis the second refrigerant and discharges high-pressure gas refrigerant.The four-way switching valve 34 functions as a switching device andmakes connection indicated by the solid lines in FIG. 1 during coolingoperation and connection indicated by the broken lines in FIG. 1 duringheating operation.

The cascade heat exchanger 35 exchanges heat between the firstrefrigerant and the second refrigerant. The cascade heat exchanger 35is, for example, a plate heat exchanger. The cascade heat exchanger 35includes a first refrigerant passage 351 and a second refrigerantpassage 352. The first refrigerant passage 351 allows the firstrefrigerant to pass therethrough. The second refrigerant passage 352allows the second refrigerant to pass therethrough. The cascade heatexchanger 35 functions as an evaporator for the first refrigerant and acondenser for the second refrigerant during cooling operation andfunctions as an evaporator for the first refrigerant and a condenser forthe second refrigerant during heating operation.

The liquid shutoff valve 38 and the gas shutoff valve 39 shut off a flowpath in which the second refrigerant circulates, for example, duringwork of installation of the cascade unit 30.

(2-3) Usage Unit 50

The usage unit 50 is configured to supply cold or heat to a user. Theusage unit 50 includes a usage heat exchanger 51 and a usage expansionvalve 52. The usage heat exchanger 51 is configured to cause cold orheat to be used by a user. The usage heat exchanger 51 is a microchannelheat exchanger and includes a flat multi-hole pipe. The usage expansionvalve 52 adjusts the amount of the second refrigerant that circulates inthe secondary-side cycle 40. The usage expansion valve 52 also functionsas a decompression device that decompresses the second refrigerant.

(2-4) Primary-Side Connection Pipe

A primary-side connection pipe includes a primary-side liquid connectionpipe 21 and a primary-side gas connection pipe 22. The primary-sideliquid connection pipe 21 connects the liquid shutoff valve 18 of theheat source unit 10 and the cascade unit 30. The primary-side gasconnection pipe 22 connects the gas shutoff valve 19 of the heat sourceunit 10 and the cascade unit 30.

(2-5) Secondary-Side Connection Pipe

A secondary-side connection pipe includes a secondary-side liquidconnection pipe 41 and a secondary-side gas connection pipe 42. Thesecondary-side liquid connection pipe 41 connects the liquid shutoffvalve 38 of the cascade unit 30 and the usage unit 50. Thesecondary-side gas connection pipe 42 connects the gas shutoff valve 39of the cascade unit 30 and the usage unit 50.

(3) Operation

(3-1) Cooling Operation

(3-1-1) Operation of Primary-Side Cycle 20

The compressor 11 sucks low-pressure gas refrigerant that is the firstrefrigerant and discharges high-pressure gas refrigerant. Thehigh-pressure gas refrigerant reaches the heat-source heat exchanger 13via the four-way switching valve 12. The heat-source heat exchanger 13condenses the high-pressure gas refrigerant and thereby produceshigh-pressure liquid refrigerant. At this time, the refrigerant that isthe first refrigerant releases heat into outside air. The high-pressureliquid refrigerant passes through the heat-source expansion valve 14that is full opened, passes through the subcooling heat exchanger 16,and reaches the primary-side expansion valve 31 via the liquid shutoffvalve 18 and the primary-side liquid connection pipe 21. Theprimary-side expansion valve 31 whose opening degree is appropriatelyset decompresses the high-pressure liquid refrigerant and therebyproduces low-pressure gas-liquid two-phase refrigerant. The low-pressuregas-liquid two-phase refrigerant enters the first refrigerant passage351 of the cascade heat exchanger 35. The cascade heat exchanger 35evaporates the low-pressure gas-liquid two-phase refrigerant and therebyproduces low-pressure gas refrigerant. At this time, the firstrefrigerant absorbs heat from the second refrigerant. The low-pressuregas refrigerant exits the first refrigerant passage 351, passes throughthe primary-side gas connection pipe 22 and the gas shutoff valve 19,and is sucked by the compressor 11 via the four-way switching valve 12.

A portion of the high-pressure liquid refrigerant that has exited theheat-source expansion valve 14 is decompressed by the subcoolingexpansion valve 15 whose opening degree is appropriately set, andbecomes gas-liquid two-phase cooling gas. The cooling gas passes throughthe subcooling heat exchanger 16. At this time, the cooling gas coolsthe high-pressure liquid refrigerant and thereby gives a degree ofsubcooling. The cooling gas exits the subcooling heat exchanger 16,mixes with the low-pressure gas refrigerant that comes from the four-wayswitching valve 12, and is sucked by the compressor 11.

(3-1-2) Operation of Secondary-Side Cycle 40

The compressor 33 sucks low-pressure gas refrigerant that is the secondrefrigerant and discharges high-pressure gas refrigerant. Thehigh-pressure gas refrigerant enters the second refrigerant passage 352of the cascade heat exchanger 35 via the four-way switching valve 34.The cascade heat exchanger 35 condenses the high-pressure gasrefrigerant and thereby produces high-pressure liquid refrigerant. Atthis time, the second refrigerant releases heat into the firstrefrigerant. The high-pressure liquid refrigerant exits the secondrefrigerant passage 352 and reaches the secondary-side expansion valve32. The secondary-side expansion valve 32 whose opening degree isappropriately set decompresses the high-pressure liquid refrigerant andthereby produces low-pressure gas-liquid two-phase refrigerant. Thelow-pressure gas-liquid two-phase refrigerant passes through the liquidshutoff valve 38 and the secondary-side liquid connection pipe 41 andreaches the usage expansion valve 52. The usage expansion valve 52 whoseopening degree is appropriately set further reduces the pressure of thelow-pressure gas-liquid two-phase refrigerant. The low-pressuregas-liquid two-phase refrigerant reaches the usage heat exchanger 51.The usage heat exchanger 51 evaporates the low-pressure gas-liquidtwo-phase refrigerant and thereby produces low-pressure gas refrigerant.At this time, the refrigerant that is the second refrigerant absorbsheat from an environment in which a user is present. The low-pressuregas refrigerant exits the usage heat exchanger 51, passes through thesecondary-side gas connection pipe 42 and the gas shutoff valve 39, andis sucked by the compressor 33 via the four-way switching valve 12.

(3-2) Heating Operation

(3-2-1) Operation of Primary-Side Cycle 20

The compressor 11 sucks low-pressure gas refrigerant that is the firstrefrigerant and discharges high-pressure gas refrigerant. Thehigh-pressure gas refrigerant passes through the gas shutoff valve 19and the primary-side gas connection pipe 22 via the four-way switchingvalve 12 and enters the first refrigerant passage 351 of the cascadeheat exchanger 35. The cascade heat exchanger 35 condenses thehigh-pressure gas refrigerant and thereby produces high-pressure liquidrefrigerant. At this time, the first refrigerant releases heat into thesecond refrigerant. The high-pressure liquid refrigerant passes throughthe primary-side expansion valve 31 that is full opened, then passesthrough the primary-side liquid connection pipe 21, the liquid shutoffvalve 18, and the subcooling heat exchanger 16, and reaches theheat-source expansion valve 14. The heat-source expansion valve 14 whoseopening degree is appropriately set decompresses the high-pressureliquid refrigerant and thereby produces low-pressure gas-liquidtwo-phase refrigerant. The low-pressure gas-liquid two-phase refrigerantreaches the heat-source heat exchanger 13. The heat-source heatexchanger 13 evaporates the low-pressure gas-liquid two-phaserefrigerant and thereby produces low-pressure gas refrigerant. At thistime, the refrigerant that is the first refrigerant absorbs heat fromoutside air. The low-pressure gas refrigerant passes through thefour-way switching valve 12 and is sucked by the compressor 11.

(3-2-2) Operation of Secondary-Side Cycle 40

The compressor 33 sucks low-pressure gas refrigerant that is the secondrefrigerant and discharges high-pressure gas refrigerant. Thehigh-pressure gas refrigerant passes through the gas shutoff valve 39and the secondary-side gas connection pipe 42 via the four-way switchingvalve 34 and reaches the usage heat exchanger 51. The usage heatexchanger 51 condenses the high-pressure gas refrigerant and therebyproduces high-pressure liquid refrigerant. At this time, the refrigerantthat is the second refrigerant releases heat into an environment inwhich a user is present. The high-pressure liquid refrigerant reachesthe usage expansion valve 52. The usage expansion valve 52 whose openingdegree is appropriately set decompresses the high-pressure liquidrefrigerant and thereby produces low-pressure gas-liquid two-phaserefrigerant. The low-pressure gas-liquid two-phase refrigerant passesthrough the secondary-side liquid connection pipe 41 and the liquidshutoff valve 38 and reaches the secondary-side expansion valve 32. Thesecondary-side expansion valve 32 whose opening degree is appropriatelyset further reduces the pressure of the low-pressure gas-liquidtwo-phase refrigerant. The low-pressure gas-liquid two-phase refrigerantenters the second refrigerant passage 352 of the cascade heat exchanger35. The cascade heat exchanger 35 evaporates the low-pressure gas-liquidtwo-phase refrigerant and thereby produces low-pressure gas refrigerant.At this time, the second refrigerant absorbs heat from the firstrefrigerant. The low-pressure gas refrigerant exits the secondrefrigerant passage 352, passes through the four-way switching valve 34,and is sucked by the compressor 33.

(4) Pipe Diameter of Secondary-Side Connection Pipe

Examples of the pipe diameter of the secondary-side connection pipe arepresented in Table 1 to Table 6. In the fields of “HORSEPOWER” and“COOLING CAPACITY”, values of a capacity that should be achieved areindicated in different units. In the field of “SINGLE”, pipe diametersof the gas connection pipe and the liquid connection pipe that arerequired to achieve the capacity indicated by “REFRIGERATING CAPACITY”in a single cycle are indicated. In the field of “DUAL”, pipe diametersof the secondary-side gas connection pipe 42 and the secondary-sideliquid connection pipe 41 that are required to achieve the capacityindicated by “REFRIGERATING CAPACITY” in a dual cycle are indicated.

The pipe diameter of the primary-side gas connection pipe 22 and theprimary-side liquid connection pipe 21 in the dual cycle are the same asthose indicated in the field of the “SINGLE”.

Regarding the pipe diameters, the values indicated in millimeter unit inthe tables indicate pipes that are manufactured according to a standardbased on inch unit. That is, the value 4.8 mm indicates 3/16 inches. Thevalue 6.4 mm indicates ¼ inches. The value 7.9 mm indicates 5/16 inches.The value 9.5 mm indicates ⅜ inches. The value 12.7 mm indicates ½inches. The value 15.9 mm indicates ⅝ inches. The value 19.1 mmindicates ¾ inches. The value 22.2 mm indicates ⅞ inches. The value 25.4mm indicates 1 inch. The value 28.6 mm indicates 9/8 inches. The value31.8 mm indicates 5/4 inches. The value 38.1 mm indicates 3/2 inches.The value 44.5 mm indicates 7/4 inches. The value 50.8 mm indicates 2inches. The value 63.5 mm indicates 5/2 inches.

(4-1) When Refrigerant is Carbon Dioxide

In Table 1, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses carbon dioxide as refrigerant are indicated.

TABLE 1 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:CO2) SINGLE DUAL GAS LIQUID GAS LIQUID PIPE PIPE PIPE PIPE COOLING DIAM-DIAM- DIAM- DIAM- HORSEPOWER CAPACITY ETER ETER ETER ETER (HP) (kW) (mm)(mm) (mm) (mm) 0.8 2.2 Φ7.9 Φ4.8 Φ7.9 Φ4.8 1 2.8 Φ7.9 Φ4.8 Φ7.9 Φ4.8 1.33.6 Φ7.9 Φ4.8 Φ7.9 Φ4.8 1.6 4.5 Φ7.9 Φ4.8 Φ7.9 Φ4.8 2 5.6 Φ9.5 Φ4.8 Φ7.9Φ4.8 2.5 7.1 Φ9.5 Φ6.4 Φ9.5 Φ4.8 2.9 8 Φ12.7 Φ6.4 Φ9.5 Φ4.8 3.2 9 Φ12.7Φ6.4 Φ9.5 Φ6.4 4 11.2 Φ12.7 Φ6.4 Φ12.7 Φ6.4 5 14 Φ12.7 Φ7.9 Φ12.7 Φ6.4 616 Φ12.7 Φ7.9 Φ12.7 Φ6.4 8 22.4 Φ15.9 Φ9.5 Φ12.7 Φ7.9 10 28 Φ15.9 Φ9.5Φ15.9 Φ7.9 12 33.5 Φ19.1 Φ9.5 Φ15.9 Φ9.5 14 40 Φ19.1 Φ12.7 Φ15.9 Φ9.5 1645 Φ19.1 Φ12.7 Φ19.1 Φ9.5 18 50 Φ19.1 Φ12.7 Φ19.1 Φ12.7 20 56 Φ22.2Φ12.7 Φ19.1 Φ12.7 22 61.5 Φ22.2 Φ12.7 Φ19.1 Φ12.7 24 69 Φ22.2 Φ12.7Φ22.2 Φ12.7 26 73 Φ22.2 Φ15.9 Φ22.2 Φ12.7 28 80 Φ22.2 Φ15.9 Φ22.2 Φ12.730 85 Φ25.4 Φ15.9 Φ22.2 Φ12.7 32 90 Φ25.4 Φ15.9 Φ22.2 Φ12.7 34 95 Φ25.4Φ15.9 Φ22.2 Φ12.7 36 100 Φ25.4 Φ15.9 Φ22.2 Φ15.9 38 109 Φ25.4 Φ15.9Φ25.4 Φ15.9 40 112 Φ25.4 Φ15.9 Φ25.4 Φ15.9 42 118 Φ28.6 Φ15.9 Φ25.4Φ15.9 44 125 Φ28.6 Φ19.1 Φ25.4 Φ15.9 46 132 Φ28.6 Φ19.1 Φ25.4 Φ15.9 48136 Φ28.6 Φ19.1 Φ25.4 Φ15.9 50 140 Φ28.6 Φ19.1 Φ25.4 Φ15.9 52 145 Φ28.6Φ19.1 Φ25.4 Φ15.9 54 150 Φ28.6 Φ19.1 Φ28.6 Φ15.9

When the refrigerating capacity of the secondary-side cycle 40 is 4.5 kWor more and 5.6 kW or less, the pipe diameter of the secondary-side gasconnection pipe 42 is 7.9 mm. This pipe diameter is smaller than thepipe diameter 9.5 mm of a gas connection pipe in a single cycle havingthe same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 7.1 kWor more and 9.0 kW or less, the pipe diameter of the secondary-side gasconnection pipe 42 is 9.5 mm. This pipe diameter is smaller than thepipe diameter 12.7 mm of a gas connection pipe in a single cycle havingthe same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 16 kWor more and 22.4 kW or less, the pipe diameter of the secondary-side gasconnection pipe 42 is 12.7 mm. This pipe diameter is smaller than thepipe diameter 15.9 mm of a gas connection pipe in a single cycle havingthe same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 5.6 kWor more and 8.0 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 4.8 mm. This pipe diameter is smaller thanthe pipe diameter 6.4 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 11.2kW or more and 16 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 6.4 mm. This pipe diameter is smaller thanthe pipe diameter 7.9 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 16 kWor more and 28 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 7.9 mm. This pipe diameter is smaller thanthe pipe diameter 9.5 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 33.5kW or more and 45 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 9.5 mm. This pipe diameter is smaller thanthe pipe diameter 12.7 mm of a liquid connection pipe in a single cyclehaving the same capacity.

(4-2) When Refrigerant is R32

In table 2, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses R32 as refrigerant are indicated.

TABLE 2 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:R32) SINGLE DUAL GAS LIQUID GAS LIQUID PIPE PIPE PIPE PIPE COOLING DIAM-DIAM- DIAM- DIAM- HORSEPOWER CAPACITY ETER ETER ETER ETER (HP) (kW) (mm)(mm) (mm) (mm) 0.8 2.2 Φ9.5 Φ4.8 Φ9.5 Φ4.8 1 2.8 Φ9.5 Φ4.8 Φ9.5 Φ4.8 1.33.6 Φ9.5 Φ6.4 Φ9.5 Φ4.8 1.6 4.5 Φ12.7 Φ6.4 Φ12.7 Φ6.4 2 5.6 Φ12.7 Φ6.4Φ12.7 Φ6.4 2.5 7.1 Φ12.7 Φ6.4 Φ12.7 Φ6.4 2.9 8 Φ12.7 Φ6.4 Φ12.7 Φ6.4 3.29 Φ12.7 Φ6.4 Φ12.7 Φ6.4 4 11.2 Φ15.9 Φ7.9 Φ15.9 Φ7.9 5 14 Φ15.9 Φ7.9Φ15.9 Φ7.9 6 16 Φ15.9 Φ9.5 Φ15.9 Φ7.9 8 22.4 Φ19.1 Φ9.5 Φ15.9 Φ9.5 10 28Φ19.1 Φ9.5 Φ19.1 Φ9.5 12 33.5 Φ22.2 Φ12.7 Φ19.1 Φ9.5 14 40 Φ22.2 Φ12.7Φ22.2 Φ12.7 16 45 Φ25.4 Φ12.7 Φ22.2 Φ12.7 18 50 Φ25.4 Φ12.7 Φ22.2 Φ12.720 56 Φ25.4 Φ12.7 Φ22.2 Φ12.7 22 61.5 Φ25.4 Φ12.7 Φ25.4 Φ12.7 24 69Φ25.4 Φ12.7 Φ25.4 Φ12.7 26 73 Φ28.6 Φ15.9 Φ25.4 Φ12.7 28 80 Φ28.6 Φ15.9Φ25.4 Φ12.7 30 85 Φ28.6 Φ15.9 Φ28.6 Φ15.9 32 90 Φ28.6 Φ15.9 Φ28.6 Φ15.934 95 Φ28.6 Φ15.9 Φ28.6 Φ15.9 36 100 Φ28.6 Φ15.9 Φ28.6 Φ15.9 38 109Φ31.8 Φ15.9 Φ28.6 Φ15.9 40 112 Φ31.8 Φ15.9 Φ28.6 Φ15.9 42 118 Φ31.8Φ15.9 Φ31.8 Φ15.9 44 125 Φ31.8 Φ15.9 Φ31.8 Φ15.9 46 132 Φ31.8 Φ15.9Φ31.8 Φ15.9 48 136 Φ38.1 Φ19.1 Φ31.8 Φ15.9 50 140 Φ38.1 Φ19.1 Φ31.8Φ15.9 52 145 Φ38.1 Φ19.1 Φ31.8 Φ15.9 54 150 Φ38.1 Φ19.1 Φ31.8 Φ15.9

When the refrigerating capacity of the secondary-side cycle 40 is 16 kWor more and 22.4 kW or less, the pipe diameter of the secondary-side gasconnection pipe 42 is 15.9 mm. This pipe diameter is smaller than thepipe diameter 19.1 mm of a gas connection pipe in a single cycle havingthe same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 2.8 kWor more and 3.6 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 4.8 mm. This pipe diameter is smaller thanthe pipe diameter 6.4 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 14 kWor more and 16 kW or less, the pipe diameter of the secondary-sideliquid connection pipe is 7.9 mm. This pipe diameter is smaller than thepipe diameter 9.5 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 28 kWor more and 33.5 kW or less, the pipe diameter of the secondary-sideliquid connection pipe is 9.5 mm. This pipe diameter is smaller than thepipe diameter 12.7 mm of a liquid connection pipe in a single cyclehaving the same capacity.

(4-3) When Refrigerant is R454B

In Table 3, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses R454B as refrigerant are indicated.

TABLE 3 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:R454B) SINGLE DUAL GAS LIQUID GAS LIQUID PIPE PIPE PIPE PIPE COOLINGDIAM- DIAM- DIAM- DIAM- HORSEPOWER CAPACITY ETER ETER ETER ETER (HP)(kW) (mm) (mm) (mm) (mm) 0.8 2.2 Φ12.7 Φ6.4 Φ12.7 Φ6.4 1 2.8 Φ12.7 Φ6.4Φ12.7 Φ6.4 1.3 3.6 Φ12.7 Φ6.4 Φ12.7 Φ6.4 1.6 4.5 Φ12.7 Φ6.4 Φ12.7 Φ6.4 25.6 Φ12.7 Φ6.4 Φ12.7 Φ6.4 2.5 7.1 Φ15.9 Φ9.5 Φ15.9 Φ9.5 2.9 8 Φ15.9 Φ9.5Φ15.9 Φ9.5 3.2 9 Φ15.9 Φ9.5 Φ15.9 Φ9.5 4 11.2 Φ19.1 Φ9.5 Φ15.9 Φ9.5 5 14Φ19.1 Φ9.5 Φ19.1 Φ9.5 6 16 Φ19.1 Φ9.5 Φ19.1 Φ9.5 8 22.4 Φ22.2 Φ12.7Φ19.1 Φ9.5 10 28 Φ22.2 Φ12.7 Φ22.2 Φ12.7 12 33.5 Φ25.4 Φ12.7 Φ22.2 Φ12.714 40 Φ25.4 Φ12.7 Φ25.4 Φ12.7 16 45 Φ28.6 Φ12.7 Φ25.4 Φ12.7 18 50 Φ28.6Φ15.9 Φ25.4 Φ12.7 20 56 Φ28.6 Φ15.9 Φ28.6 Φ12.7 22 61.5 Φ28.6 Φ15.9Φ28.6 Φ15.9 24 69 Φ31.8 Φ15.9 Φ28.6 Φ15.9 26 73 Φ31.8 Φ15.9 Φ28.6 Φ15.928 80 Φ31.8 Φ15.9 Φ31.8 Φ15.9 30 85 Φ31.8 Φ15.9 Φ31.8 Φ15.9 32 90 Φ38.1Φ19.1 Φ38.1 Φ15.9 34 95 Φ38.1 Φ19.1 Φ38.1 Φ15.9 36 100 Φ38.1 Φ19.1 Φ38.1Φ15.9 38 109 Φ38.1 Φ19.1 Φ38.1 Φ15.9 40 112 Φ38.1 Φ19.1 Φ38.1 Φ19.1 42118 Φ38.1 Φ19.1 Φ38.1 Φ19.1 44 125 Φ38.1 Φ19.1 Φ38.1 Φ19.1 46 132 Φ38.1Φ19.1 Φ38.1 Φ19.1 48 136 Φ38.1 Φ19.1 Φ38.1 Φ19.1 50 140 Φ44.5 Φ19.1Φ38.1 Φ19.1 52 145 Φ44.5 Φ19.1 Φ38.1 Φ19.1 54 150 Φ44.5 Φ19.1 Φ38.1Φ19.1

When the refrigerating capacity of the secondary-side cycle 40 is 9.0 kWor more and 11.2 kW or less, the pipe diameter of the secondary-side gasconnection pipe 42 is 15.9 mm. This pipe diameter is smaller than thepipe diameter 19.1 mm of a gas connection pipe in a single cycle havingthe same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 16.0kW or more and 22.4 kW or less, the pipe diameter of the secondary-sidegas connection pipe 42 is 19.1 mm. This pipe diameter is smaller thanthe pipe diameter 22.2 mm of a gas connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 16 kWor more and 22.4 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 9.5 mm. This pipe diameter is smaller thanthe pipe diameter 12.7 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 45 kWor more and 56 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 12.7 mm. This pipe diameter is smaller thanthe pipe diameter 15.9 mm of a liquid connection pipe in a single cyclehaving the same capacity.

When the refrigerating capacity of the secondary-side cycle 40 is 85 kWor more and 109 kW or less, the pipe diameter of the secondary-sideliquid connection pipe 41 is 15.9 mm. This pipe diameter is smaller thanthe pipe diameter 19.1 mm of a liquid connection pipe in a single cyclehaving the same capacity.

(4-4) When Refrigerant is R1234yf

In Table 4, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses R1234yf as refrigerant are indicated.

TABLE 4 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:R1234yf) SINGLE DUAL GAS LIQUID GAS LIQUID PIPE PIPE PIPE PIPE COOLINGDIAM- DIAM- DIAM- DIAM- HORSEPOWER CAPACITY ETER ETER ETER ETER (HP)(kW) (mm) (mm) (mm) (mm) 0.8 2.2 Φ12.7 Φ6.4 Φ12.7 Φ6.4 1 2.8 Φ15.9 Φ6.4Φ15.9 Φ6.4 1.3 3.6 Φ15.9 Φ6.4 Φ15.9 Φ6.4 1.6 4.5 Φ19.1 Φ6.4 Φ15.9 Φ6.4 25.6 Φ19.1 Φ9.5 Φ19.1 Φ6.4 2.5 7.1 Φ19.1 Φ9.5 Φ19.1 Φ9.5 2.9 8 Φ22.2 Φ9.5Φ19.1 Φ9.5 3.2 9 Φ22.2 Φ9.5 Φ22.2 Φ9.5 4 11.2 Φ22.2 Φ9.5 Φ22.2 Φ9.5 5 14Φ25.4 Φ9.5 Φ22.2 Φ9.5 6 16 Φ25.4 Φ12.7 Φ25.4 Φ9.5 8 22.4 Φ28.6 Φ12.7Φ28.6 Φ12.7 10 28 Φ31.8 Φ12.7 Φ28.6 Φ12.7 12 33.5 Φ38.1 Φ12.7 Φ31.8Φ12.7 14 40 Φ38.1 Φ15.9 Φ38.1 Φ12.7 16 45 Φ38.1 Φ15.9 Φ38.1 Φ15.9 18 50Φ38.1 Φ15.9 Φ38.1 Φ15.9 20 56 Φ44.5 Φ15.9 Φ38.1 Φ15.9 22 61.5 Φ44.5Φ15.9 Φ38.1 Φ15.9 24 69 Φ44.5 Φ19.1 Φ44.5 Φ15.9 26 73 Φ44.5 Φ19.1 Φ44.5Φ15.9 28 80 Φ44.5 Φ19.1 Φ44.5 Φ15.9 30 85 Φ44.5 Φ19.1 Φ44.5 Φ19.1 32 90Φ50.8 Φ19.1 Φ44.5 Φ19.1 34 95 Φ50.8 Φ19.1 Φ44.5 Φ19.1 36 100 Φ50.8 Φ19.1Φ44.5 Φ19.1 38 109 Φ50.8 Φ19.1 Φ50.8 Φ19.1 40 112 Φ50.8 Φ19.1 Φ50.8Φ19.1 42 118 Φ50.8 Φ22.2 Φ50.8 Φ19.1 44 125 Φ63.5 Φ22.2 Φ50.8 Φ19.1 46132 Φ63.5 Φ22.2 Φ50.8 Φ19.1 48 136 Φ63.5 Φ22.2 Φ50.8 Φ19.1 50 140 Φ63.5Φ22.2 Φ50.8 Φ19.1 52 145 Φ63.5 Φ22.2 Φ63.5 Φ22.2 54 150 Φ63.5 Φ22.2Φ63.5 Φ22.2

(4-5) When Refrigerant is R1234ze

In Table 5, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses R1234ze as refrigerant are indicated.

TABLE 5 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:R1234ze) SINGLE DUAL GAS LIQUID GAS LIQUID PIPE PIPE PIPE PIPE COOLINGDIAM- DIAM- DIAM- DIAM- HORSEPOWER CAPACITY ETER ETER ETER ETER (HP)(kW) (mm) (mm) (mm) (mm) 0.8 2.2 Φ15.9 Φ6.4 Φ15.9 Φ6.4 1 2.8 Φ15.9 Φ6.4Φ15.9 Φ6.4 1.3 3.6 Φ15.9 Φ6.4 Φ15.9 Φ6.4 1.6 4.5 Φ19.1 Φ6.4 Φ19.1 Φ6.4 25.6 Φ19.1 Φ9.5 Φ19.1 Φ6.4 2.5 7.1 Φ22.2 Φ9.5 Φ19.1 Φ9.5 2.9 8 Φ22.2 Φ9.5Φ22.2 Φ9.5 3.2 9 Φ22.2 Φ9.5 Φ22.2 Φ9.5 4 11.2 Φ25.4 Φ9.5 Φ22.2 Φ9.5 5 14Φ25.4 Φ9.5 Φ25.4 Φ9.5 6 16 Φ28.6 Φ12.7 Φ25.4 Φ9.5 8 22.4 Φ31.8 Φ12.7Φ28.6 Φ12.7 10 28 Φ38.1 Φ12.7 Φ31.8 Φ12.7 12 33.5 Φ38.1 Φ12.7 Φ38.1Φ12.7 14 40 Φ38.1 Φ12.7 Φ38.1 Φ12.7 16 45 Φ44.5 Φ15.9 Φ38.1 Φ12.7 18 50Φ44.5 Φ15.9 Φ38.1 Φ15.9 20 56 Φ44.5 Φ15.9 Φ44.5 Φ15.9 22 61.5 Φ44.5Φ15.9 Φ44.5 Φ15.9 24 69 Φ44.5 Φ15.9 Φ44.5 Φ15.9 26 73 Φ50.8 Φ15.9 Φ44.5Φ15.9 28 80 Φ50.8 Φ19.1 Φ44.5 Φ15.9 30 85 Φ50.8 Φ19.1 Φ50.8 Φ15.9 32 90Φ50.8 Φ19.1 Φ50.8 Φ15.9 34 95 Φ50.8 Φ19.1 Φ50.8 Φ19.1 36 100 Φ50.8 Φ19.1Φ50.8 Φ19.1 38 109 Φ63.5 Φ19.1 Φ50.8 Φ19.1 40 112 Φ63.5 Φ19.1 Φ50.8Φ19.1 42 118 Φ63.5 Φ19.1 Φ50.8 Φ19.1 44 125 Φ63.5 Φ19.1 Φ63.5 Φ19.1 46132 Φ63.5 Φ19.1 Φ63.5 Φ19.1 48 136 Φ63.5 Φ19.1 Φ63.5 Φ19.1 50 140 Φ63.5Φ22.2 Φ63.5 Φ19.1 52 145 Φ63.5 Φ22.2 Φ63.5 Φ19.1 54 150 Φ63.5 Φ22.2Φ63.5 Φ19.1

(4-6) When Refrigerant is Mixture Refrigerant

In Table 6, pipe diameters of the secondary-side gas connection pipe 42and the secondary-side liquid connection pipe 41 in the refrigerantcycle system 100 that uses, as refrigerant, mixture refrigerantconstituted by R32, R1234yf, and R1123 are indicated. Here, percentagesof R32, R1234yf, and R1123 in the mixture refrigerant are 21.5%, 18.5%,and 60%, respectively.

TABLE 6 PIPE DIAMETER OF SECONDARY-SIDE CONNECTION PIPE (REFRIGERANT:R32/R1234yf/R1123 (21.5%/18.5%/60%) MIXTURE) SINGLE DUAL GAS LIQUID GASLIQUID PIPE PIPE PIPE PIPE COOLING DIAM- DIAM- DIAM- DIAM- HORSEPOWERCAPACITY ETER ETER ETER ETER (HP) (kW) (mm) (mm) (mm) (mm) 0.8 2.2 Φ12.7Φ6.4 Φ12.7 Φ6.4 1 2.8 Φ12.7 Φ6.4 Φ12.7 Φ6.4 1.3 3.6 Φ12.7 Φ6.4 Φ12.7Φ6.4 1.6 4.5 Φ12.7 Φ6.4 Φ12.7 Φ6.4 2 5.6 Φ12.7 Φ9.5 Φ12.7 Φ6.4 2.5 7.1Φ15.9 Φ9.5 Φ15.9 Φ9.5 2.9 8 Φ15.9 Φ9.5 Φ15.9 Φ9.5 3.2 9 Φ15.9 Φ9.5 Φ15.9Φ9.5 4 11.2 Φ19.1 Φ9.5 Φ15.9 Φ9.5 5 14 Φ19.1 Φ9.5 Φ19.1 Φ9.5 6 16 Φ19.1Φ12.7 Φ19.1 Φ9.5 8 22.4 Φ22.2 Φ12.7 Φ19.1 Φ12.7 10 28 Φ22.2 Φ12.7 Φ22.2Φ12.7 12 33.5 Φ25.4 Φ12.7 Φ22.2 Φ12.7 14 40 Φ25.4 Φ15.9 Φ25.4 Φ12.7 1645 Φ28.6 Φ15.9 Φ25.4 Φ12.7 18 50 Φ28.6 Φ15.9 Φ25.4 Φ15.9 20 56 Φ28.6Φ15.9 Φ25.4 Φ15.9 22 61.5 Φ28.6 Φ15.9 Φ28.6 Φ15.9 24 69 Φ31.8 Φ15.9Φ28.6 Φ15.9 26 73 Φ31.8 Φ19.1 Φ28.6 Φ15.9 28 80 Φ31.8 Φ19.1 Φ28.6 Φ15.930 85 Φ31.8 Φ19.1 Φ31.8 Φ15.9 32 90 Φ38.1 Φ19.1 Φ31.8 Φ15.9 34 95 Φ38.1Φ19.1 Φ31.8 Φ19.1 36 100 Φ38.1 Φ19.1 Φ31.8 Φ19.1 38 109 Φ38.1 Φ19.1Φ31.8 Φ19.1 40 112 Φ38.1 Φ19.1 Φ38.1 Φ19.1 42 118 Φ38.1 Φ19.1 Φ38.1Φ19.1 44 125 Φ38.1 Φ22.2 Φ38.1 Φ19.1 46 132 Φ38.1 Φ22.2 Φ38.1 Φ19.1 48136 Φ38.1 Φ22.2 Φ38.1 Φ19.1 50 140 Φ44.5 Φ22.2 Φ38.1 Φ19.1 52 145 Φ44.5Φ22.2 Φ38.1 Φ19.1 54 150 Φ44.5 Φ22.2 Φ38.1 Φ19.1

(5) Features

(5-1)

The pipe diameter of the connection pipe in the secondary-side cycle 40is smaller than the pipe diameter of the connection pipe in theprimary-side cycle 20. Consequently, it is possible to increase the flowspeed of refrigerant in the secondary-side cycle. Therefore, arefrigerating-machine oil that has flowed out from the compressor easilyreturns to the compressor.

(5-2)

The pipe diameter of the secondary-side gas connection pipe 42 may beless than or equal to 90% of the pipe diameter of the primary-side gasconnection pipe 22, or the pipe diameter of the secondary-side liquidconnection pipe 41 may be less than or equal to 90% of the pipe diameterof the primary-side liquid connection pipe 21.

(5-3)

The compression ratio of the secondary-side cycle 40 may be smaller thanthe compression ratio of the primary-side cycle 20.

(6) Modifications

In the embodiments described above, the refrigerant cycle system 100includes the one heat source unit 10, the one cascade unit 30, and theone usage unit 50. Instead of this, the refrigerant cycle system 100 mayinclude the one heat source unit 10, a plurality of the cascade units30, and a plurality of the usage units 50.

CONCLUSION

Although the disclosure has been described with respect to only alimited number of embodiments, those skilled in the art, having benefitof this disclosure, will appreciate that various other embodiments maybe devised without departing from the scope of the present disclosure.Accordingly, the scope of the disclosure should be limited only by theattached claims.

REFERENCE SIGNS LIST

10 heat source unit

13 heat-source heat exchanger

20 primary-side cycle

21 primary-side liquid connection pipe

22 primary-side gas connection pipe

30 cascade unit

35 cascade heat exchanger

40 secondary-side cycle

41 secondary-side liquid connection pipe

42 secondary-side gas connection pipe

50 usage unit

52 usage expansion valve

100 refrigerant cycle system

PATENT LITERATURE

PTL 1: Japanese Patent Application Laid-Open Publication No. 2014-74508

1. A refrigerant cycle system comprising: a primary-side cycle of avapor compression type, wherein the primary-side cycle circulates afirst refrigerant; a secondary-side cycle of a vapor compression type,wherein the secondary-side cycle circulates a second refrigerant; and acascade heat exchanger that exchanges heat between the first refrigerantand the second refrigerant, wherein the primary-side cycle comprises: aheat-source heat exchanger for giving cold or heat to the firstrefrigerant; and a primary-side connection pipe that connects thecascade heat exchanger and the heat-source heat exchanger, thesecondary-side cycle comprises: a usage heat exchanger for using thecold or the heat obtained by the second refrigerant from the cascadeheat exchanger; and a secondary-side connection pipe that connects thecascade heat exchanger and the usage heat exchanger, the primary-sideconnection pipe comprises: a primary-side gas connection pipe; and aprimary-side liquid connection pipe, the secondary-side connection pipecomprises: a secondary-side gas connection pipe; and a secondary-sideliquid connection pipe, and at least one of the following is satisfied:a pipe diameter of the secondary-side gas connection pipe is smallerthan a pipe diameter of the primary-side gas connection pipe, and a pipediameter of the secondary-side liquid connection pipe is smaller than apipe diameter of the primary-side liquid connection pipe.
 2. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 4.5 kW or more and 5.6 kW or less, and the pipediameter of the secondary-side gas connection pipe is 5/16 inch.
 3. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 7.1 kW or more and 9.0 kW or less, and the pipediameter of the secondary-side gas connection pipe is ⅜ inch.
 4. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 16 kW or more and 22.4 kW or less, and the pipediameter of the secondary-side gas connection pipe is ½ inch.
 5. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 5.6 kW or more and 8.0 kW or less, and the pipediameter of the secondary-side liquid connection pipe is 3/16 inch. 6.The refrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 11.2 kW or more and 16 kW or less, and the pipediameter of the secondary-side liquid connection pipe is ¼ inch.
 7. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 16 kW or more and 28 kW or less, and the pipediameter of the secondary-side liquid connection pipe is 5/16 inch. 8.The refrigerant cycle system according to claim 1, wherein the secondrefrigerant is carbon dioxide, a refrigerating capacity of thesecondary-side cycle is 33.5 kW or more and 45 kW or less, and the pipediameter of the secondary-side liquid connection pipe is ⅜ inch.
 9. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is R32, a refrigerating capacity of the secondary-side cycleis 16 kW or more and 22.4 kW or less, and the pipe diameter of thesecondary-side gas connection pipe is ⅝ inch.
 10. The refrigerant cyclesystem according to claim 1, wherein the second refrigerant is R32, arefrigerating capacity of the secondary-side cycle is 2.8 kW or more and3.6 kW or less, and the pipe diameter of the secondary-side liquidconnection pipe is 3/16 inch.
 11. The refrigerant cycle system accordingto claim 1, wherein the second refrigerant is R32, a refrigeratingcapacity of the secondary-side cycle is 14 kW or more and 16 kW or less,and the pipe diameter of the secondary-side liquid connection pipe is5/16 inch.
 12. The refrigerant cycle system according to claim 1,wherein the second refrigerant is R32, a refrigerating capacity of thesecondary-side cycle is 28 kW or more and 33.5 kW or less, and the pipediameter of the secondary-side liquid connection pipe is ⅜ inch.
 13. Therefrigerant cycle system according to claim 1, wherein the secondrefrigerant is R454B, a refrigerating capacity of the secondary-sidecycle is 9.0 kW or more and 11.2 kW or less, and the pipe diameter ofthe secondary-side gas connection pipe is ⅝ inch.
 14. The refrigerantcycle system according to claim 1, wherein the second refrigerant isR454B, a refrigerating capacity of the secondary-side cycle is 16.0 kWor more and 22.4 kW or less, and the pipe diameter of the secondary-sidegas connection pipe is ¾ inch.
 15. The refrigerant cycle systemaccording to claim 1, wherein the second refrigerant is R454B, arefrigerating capacity of the secondary-side cycle is 16 kW or more and22.4 kW or less, and the pipe diameter of the secondary-side liquidconnection pipe is ⅜ inch.
 16. The refrigerant cycle system according toclaim 1, wherein the second refrigerant is R454B, a refrigeratingcapacity of the secondary-side cycle is 45 kW or more and 56 kW or less,and the pipe diameter of the secondary-side liquid connection pipe is ½inch.
 17. The refrigerant cycle system according to claim 1, wherein thesecond refrigerant is R454B, a refrigerating capacity of thesecondary-side cycle is 85 kW or more and 109 kW or less, and the pipediameter of the secondary-side liquid connection pipe is ⅝ inch.
 18. Therefrigerant cycle system according to claim 1, wherein at least one ofthe following is satisfied: the pipe diameter of the secondary-side gasconnection pipe is less than or equal to 90% of the pipe diameter of theprimary-side gas connection pipe, and the pipe diameter of thesecondary-side liquid connection pipe is less than or equal to 90% ofthe pipe diameter of the primary-side liquid connection pipe.
 19. Therefrigerant cycle system according to claim 1, wherein a compressionratio of the secondary-side cycle is smaller than a compression ratio ofthe primary-side cycle.